Speech and Language

It is the highest function of the nervous system Involves understanding of spoken & printed words It is the ability to express ideas in speech & writing

Types of speech Spoken speech: understanding spoken words & expressing ideas in speech Written speech: understanding written words and expressing ideas in writing

Areas involved 1- Wernicke`s area: At the posterior end of the superior temporal gyrus Closely associated with 1 & 2 auditory areas Responsible about comprehension of auditory & visual information, then project it to Broca`s area via arcuat fasiculus

1- Wernicke`s area (cont.) Interpretations of sensory experience Formation of thought in response to sensory experience Choice of words to express thoughts

2- Broca`s area: At the lower end of premotor area Process information received from W. area into detailed & co-ordinated pattern for vocalization Then project it to motor cortex to initiate the appropriate movement of the lips & larynx to produces speech

2- Broca`s area (cont.): In adult who learn second language during adulthood. The MRI shows portion of Broca`s area concerned with it is adjacent to but separate from area concerned with the native language But in children who learn second language early in life there is only single area involved for both languages

3- Arcuate fasiculus

4- Agular Gyrus Leis behind Wernikes area fused posteriorly into the visual cortex Function: interpretation of information obtained from reading from visual cortex

W. area receive information from both auditory & visual areas Project it to B. areas via arcuat fasiculus Broca`s area process information received into co-ordinated pattern of vocalization & then project that pattern to the motor area Initiation of movement of muscle of speech in tongue, larynx & lips

If writing is concerned, then information received from W If writing is concerned, then information received from W. area is processed in the area of hand skills »»»»»» co-ordinated pattern of muscle movement projected to the arms & hand region of the motor cortex »»»»»» initiation of necessary muscle movement in the hand & arms required for writing a particular word

Aphasia Abnormality of language function

Dysarthria: Abnormality in articulation (motor dysfunction) Due to neurological conditions involving motor function (upper or lower motor neuron lesion)

Dyscalculia Difficulty in learning or comprehending arithmetic and mathematics Seen in developmental disorder.

Aphasia Abnormality of language function due to injury of language centres in cerebral cortex. Comprehension or expression of words will be affected Due to thrombus or embolism of cerebral vessels, trauma

Types of Aphasia

1- Motor or Broca`s aphasia (non fluent): Lesion of Broca`s area Patient will understand spoken & written words but find it difficult to speech or to write Poorly articulated speech, slow with great effort & abnormal rhythm In some cases speech may be limited to 2-3 words

Progressive non-fluent aphasia: Insula damage: Insula is a small region of the cerebral cortex located deep within the lateral sulcus Progressive non-fluent aphasia: deterioration of normal language function non fluent + normal comprehesion Intact other non-linguistic cognition Degdegenerative disorders Atrophy of the left anterior insular cortex

2- Sensory or Wernikes aphasia (fluent): Lesion of wernikes area +/- arcuate fasucul Impaired comprehension Loss of intellectual function Failure to interprets meaning of written or spoken words Meaningless & excessive talk (in sever cases)

3- Conductive aphasia (fluent): Lesion of nerve fibres of arcuate fasiculus Patient understand speech of others but can not repeat it Meaningless speech

4- Anomic aphasia: Lesion of angular gyrus, thus B. & W. are intact Speech & auditory comprehension is normal but visual comprehension is abnormal, due to visual information is not processed & not transmitted to W. area Dyslexia (word blindness) interruption in the flow of visual experience into W. area from visual area